A, B = map(int,input().split())
S = input()
f = False
for i in range(len(S)):
    if i < A:
        if S[i].isdigit():
            continue
        else:
            f = True
    if i == A:
        if S[i] == "-":
            continue
        else:
            f = True
    if A < i < B:
        if S[i].isdigit():
            continue
        else:
            f = True
    if f:
        print("No")
        break
if not f:
    print("Yes")


