#include <bits/stdc++.h>
int main(void) {
  int a, b;
  scanf("%d %d", &a, &b);
  char code[11];
  scanf("%s", code);
  if (code[a] == '-' || code[a] - '0' >= 0 || code[a] - '0' <= 9) {
    if (strlen(code) == a + b + 1) {
      printf("Yes");
      return 0;
    }
  }
  printf("No");
  return 0;
}
