#include <cstdio>#define MAX1005int main(){unsigned n, i, a, b, c, d, ip, net;int len;while(scanf("%u", &n) == 1){scanf("%u.%u.%u.%u", &a, &b, &c, &d);net = a << 24 | b << 16 | c << 8 | d;len = 32;for(i = 1; i < n; ++i){scanf("%u.%u.%u.%u", &a, &b, &c, &d);ip = a << 24 | b << 16 | c << 8 | d;int b = 31;for(; b >= 32-len; --b){if((net & (1u << b)) ^ (ip & (1u << b))) break;}len = 31 - b;}unsigned mask = 0;for(int b = 31; b >= 32-len; --b) mask |= 1 << b;net &= mask;printf("%u.%u.%u.%un", net >> 24 & 255, net >> 16 & 255, net >> 8 & 255, net & 255);printf("%u.%u.%u.%un", mask >> 24 & 255, mask >> 16 & 255, mask >> 8 & 255, mask & 255);}return 0;}
