def judge(a, b, s):
    num = [str(i) for i in range(10)]
    for i in range(a+b+1):
        if s[i] in num or (s[a] == "-" and i == a):
            continue
        else:
            return "No"

    return "Yes"
            

A, B = map(int,input().split())
S = input()
ans  = judge(A, B, S)
print(ans)
