a=list(input())
n=len(a)
s=""
m=0
for i in range(0,n-2,2):
    s=a[i]+a[i+1]+a[i+2]
    m=int(eval(s))
    a[i+2]=str(m)
print(a[n-1])

/**************************************************************
	Problem: 1122
	User: admin
	Language: Python
	Result: Accepted
	Time:94 ms
	Memory:34480 kb
****************************************************************/