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