coursera_week4_1

def MinDivisor(n): 
    nn = n ** .5
    i = 1
    while i<nn:
        i += 1
        #print(i,nn)
        if n % i == 0 :
            break
    if i == int(nn):
        return i
    else:
        return n
    
    
x = int(input()) 
print(int(MinDivisor(x)))