#include <bits/stdc++.h>
const int N = 1e9;
const int mod = (int)1e9 + 7;
const int INF = 0x3f3f3f3f;
const double PI = acos(-1.0);
const int maxn = 1e5 + 5;
char s[100];
using namespace std;
bool cmp(int a, int b) { return a > b; }
int gcd(int a, int b) { return (b == 0) ? a : gcd(b, a % b); }
int main() {
  int a, b;
  int i, j;
  bool is;
  is = false;
  scanf("%d%d", &a, &b);
  scanf("%s", s);
  int len = strlen(s);
  if (len != a + b + 1)
    printf("No");
  else {
    for (i = 0; i < len; i++) {
      if (s[i] == '-') {
        is = true;
        break;
      }
    }
    if (is) {
      for (j = i + 1; j < len; j++)
        if (!isdigit(s[j])) {
          is = false;
          break;
        }
    }
    if (!is)
      printf("No");
    else
      printf("Yes");
  }
  return 0;
}
