from math import sqrt

count = 1
i = 1
while count < 3000:
        i += 2
        for k in range(2, 1+int(sqrt(i+1))):    #range(2, i):   
            if i%k == 0:       
                break
        else:
            #print(i) ,
            count += 1
            #if count%20==0: print ""
print i