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