#include <bits/stdc++.h>
int main() {
  int a, b, hy, len;
  char s[15];
  len = strlen(s);
  scanf("%d%d", &a, &b);
  scanf("%s", &s);
  if (s[a] == '-') {
    for (int i = 0; i < len; i++) {
      if (s[i] == '-') {
        printf("No\n");
        return 0;
      } else {
        continue;
      }
    }
    printf("Yes\n");
  } else if (s[a] != '-') {
    printf("No\n");
  }
  return 0;
}
