try {
      MathPreconditions.checkPositive("int", 0);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCheckPositive_maxInt() {
    MathPreconditions.checkPositive("int", Integer.MAX_VALUE);
  }

  public void testCheckPositive_minInt() {
    try {
      MathPreconditions.checkPositive("int", Integer.MIN_VALUE);
      fail();

    try {
      MathPreconditions.checkPositive("int", 0);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCheckPositive_maxInt() {
    MathPreconditions.checkPositive("int", Integer.MAX_VALUE);
  }

  public void testCheckPositive_minInt() {
    try {
      MathPreconditions.checkPositive("int", Integer.MIN_VALUE);
      fail();

@GwtCompatible
@ElementTypesAreNonnullByDefault
final class MathPreconditions {
  @CanIgnoreReturnValue
  static int checkPositive(String role, int x) {
    if (x <= 0) {
      throw new IllegalArgumentException(role + " (" + x + ") must be > 0");
    }
    return x;
  }

  @CanIgnoreReturnValue
  static long checkPositive(String role, long x) {
    if (x <= 0) {
      throw new IllegalArgumentException(role + " (" + x + ") must be > 0");

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.graph.Graphs.checkNonNegative;
import static com.google.common.graph.Graphs.checkPositive;
import static java.util.Objects.requireNonNull;

import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import com.google.common.collect.Sets;

import static com.google.common.graph.GraphConstants.SELF_LOOPS_NOT_ALLOWED;
import static com.google.common.graph.Graphs.checkNonNegative;
import static com.google.common.graph.Graphs.checkPositive;
import static java.util.Objects.requireNonNull;

import com.google.common.collect.ImmutableList;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import javax.annotation.CheckForNull;

/**

import static com.google.common.graph.GraphConstants.INNER_LOAD_FACTOR;
import static com.google.common.graph.Graphs.checkNonNegative;
import static com.google.common.graph.Graphs.checkPositive;

import com.google.common.base.Function;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;

import static com.google.common.math.MathPreconditions.checkNoOverflow;
import static com.google.common.math.MathPreconditions.checkNonNegative;
import static com.google.common.math.MathPreconditions.checkPositive;
import static com.google.common.math.MathPreconditions.checkRoundingUnnecessary;
import static java.lang.Math.abs;
import static java.lang.Math.min;
import static java.math.RoundingMode.HALF_EVEN;

  static long checkNonnegative(long value, String name) {
    if (value < 0) {
      throw new IllegalArgumentException(name + " cannot be negative but was: " + value);
    }
    return value;
  }

  static void checkPositive(int value, String name) {
    if (value <= 0) {
      throw new IllegalArgumentException(name + " must be positive but was: " + value);
    }
  }

  /**

  static long checkNonnegative(long value, String name) {
    if (value < 0) {
      throw new IllegalArgumentException(name + " cannot be negative but was: " + value);
    }
    return value;
  }

  static void checkPositive(int value, String name) {
    if (value <= 0) {
      throw new IllegalArgumentException(name + " must be positive but was: " + value);
    }
  }

  /**

  @CanIgnoreReturnValue
  @Override
  public int add(E element, int occurrences) {
    checkNotNull(element);
    if (occurrences == 0) {
      return count(element);
    }
    CollectPreconditions.checkPositive(occurrences, "occurrences");

    while (true) {
      AtomicInteger existingCounter = Maps.safeGet(countMap, element);
      if (existingCounter == null) {