#include <bits/stdc++.h>
int main() {
  int a, b, hitung = 0;
  scanf("%d %d", &a, &b);
  char inp[a + b + 1];
  scanf("%s", inp);
  for (int i = 0; i < a + b + 1; i++) {
    if (i != a) {
      if (inp[i] >= '0' && inp[i] <= '9') {
        hitung++;
      } else if (inp[i] == '-') {
        hitung++;
      }
    }
  }
  if (hitung == a + b + 1) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
