#include <bits/stdc++.h>
int main() {
  int a, b;
  char arr[20] = {0};
  while (~scanf("%d%d", &a, &b)) {
    getchar();
    gets(arr);
    int f = 1;
    for (int i = 0; i < a + b + 1; i++) {
      if (i != a) {
        if (!(arr[i] >= '0' && arr[i] <= '9')) {
          f = 0;
          break;
        }
      } else if (arr[i] != '-') {
        f = 0;
        break;
      }
    }
    if (f)
      printf("Yes\n");
    else
      printf("No\n");
  }
}
