A,B = map(int,input().split())
S = input()
ans = 0
ls = ["1","2","3","4","5","6","7","8","9","0"]
if S[A] == "-":
    for i in range(A+B+1):
        if S[i] in ls:
            ans += 1
if ans == (A+B+1):
    print("Yes")
else:
    print("No")