l = map(int, raw_input().split())
k = raw_input()
listed = list(k)
if (len(k) == (2 + l[0] + l[1])) and (listed[l[0]] == "-") and ((listed[l[0]+1] in range(10)) and ((listed[l[0]-1]) in range(10))):
    print "Yes"
else:
    print "No"
