#include <bits/stdc++.h>
int main() {
  int a, b;
  char s[11];
  int cnt = 0;
  int a_i = -1;
  scanf("%d %d", &a, &b);
  scanf("%s", s);
  for (int i = 0; i < a + b + 1; i++) {
    if (s[i] == '-') {
      cnt = cnt++;
      a_i = i;
    }
  }
  if (cnt == 1 || a_i == a) {
    puts("Yes");
  } else {
    puts("No");
  }
  return 0;
}
