#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  char c[255];
  scanf("%s", &c[255]);
  int count = 0;
  for (int i = 0; i < c[255]; i++) {
    if (c[a + 1] != '-') {
      printf("No\n");
      return 0;
    }
    if (c[i] >= '0' && c[i] <= '9') {
      count++;
    }
  }
  if (count + 1 == a + b) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
