#include <bits/stdc++.h>
int main() {
  int a;
  int b;
  char s[10];
  int d;
  scanf("%d %d", &a, &b);
  scanf("%s", &s);
  int panjang = strlen(s);
  int c = a + b + 1;
  if (c = panjang) {
    if (s[a] == '-') {
      if (s[0] == '-') {
        printf("No");
      } else {
        printf("Yes");
      }
    } else {
      printf("No");
    }
  }
  return 0;
}
