#include<cstdio>
int main() {
	int a,b;
	char s[12];
	scanf("%d%d", &a,&b);
	scanf("%s", s);
	for (int i = 0; i <= a+b; i++) {
		if (i==a&&s[i]!='-'||i!=a&&('0' > s[i] || s[i] > '9')) {
			printf("No");
			return 0;
		}
	}
	printf("Yes");
	return 0;
}