#include <bits/stdc++.h>
using namespace std;
int a, b;
char s[13];
int main() {
  scanf("%d %d", &a, &b);
  scanf("%s", s);
  for (int i = 0; i < (int)(a + b + 1); i++) {
    if (s[i] - '0' >= 0 && s[i] - '0' <= 9) continue;
    if (i == a && s[i] == '-') continue;
    printf("No\n");
    return 0;
  }
  printf("Yes\n");
  return 0;
}
