20.py

arr = input().split()
stek = []
for elem in arr:
    if elem in "*-+":
        res = eval(f"{stek.pop(-2)} {elem} {stek.pop(-1)}")
        stek.append(res)
    
    elif elem == "/":
        res = eval(f"{stek.pop(-2)} // {stek.pop(-1)}")
        stek.append(res)
    
    elif elem == "~":
        res = stek.pop(-1) * (-1)
        stek.append(res)
    
    elif elem == "#":
        stek.append(stek[-1])
    
    elif elem == "!":
        res = stek.pop(-1)
        prod = 1
        while res:
            prod *= res
            res -= 1
        stek.append(prod)
    
    elif elem == "@":
        a, b, c = stek.pop(-3), stek.pop(-2), stek.pop(-1)
        stek += [b, c, a]   
    
    else:
        stek.append(int(elem))

print(stek[0])