#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  char str[a + b + 1];
  scanf("%s", &str);
  if (str[a] == '-') {
    printf("Yes\n");
  }
  if (str[a] != '-') {
    printf("No\n");
  }
  return 0;
}
