#include<cstdio>
#include<cctype>

int main(){
	int A,B;
	scanf("%d %d", &A, &B);
	char S[12];
	scanf("%s", S);
	int i = 0;
	while(isdigit(S[i]))
		i++;
	if(i == A && S[A] == '-'){
		while(isdigit(S[i+1]))
			i++;
	}
	if(i == A + B)
		printf("Yes\n");
	else
		printf("No\n");
	return 0;
}