#include <bits/stdc++.h>
int main(int argc, char *argv[]) {
  int n, m;
  while (scanf("%d%d", &n, &m) != EOF) {
    char num[15];
    getchar();
    gets(num);
    int count = 0;
    for (int i = 0; i < n + m + 1; i++) {
      if (i == n) {
        if (num[n] == '-') count++;
      } else if (num[i] >= '0' && num[i] <= '9') {
        count++;
      }
    }
    if (count == n + m + 1)
      printf("Yes\n");
    else
      printf("No\n");
  }
  return 0;
}
