#include <bits/stdc++.h>
int main() {
  int a, b, total = 0;
  char s[a + b + 2];
  scanf("%d %d", &a, &b);
  scanf("%s", s);
  for (int i = 0; i < a + b + 1; i++) {
    if (i != a) {
      if (s[i] >= 48 && s[i] <= 57) {
        total++;
      }
    } else {
      if (s[i] == '-') {
        total++;
      }
    }
  }
  if (total == a + b + 1) {
    printf("Yes");
  } else {
    printf("No");
  }
  return 0;
}
