import core.stdc.stdio : getchar, printf; extern(C) void main() { slide: for (auto q = 0u, i = 1u; q & 0xffu ^ '\n'; ++i) { q <<= 8u; q |= getchar(); if (i < 4) continue; auto p = cast(ubyte*) &q; for (auto s = 0u, j = 0u; j < 4u; ++j) { auto b = 1u << (p[j] & 0x1fu); if (s & b) continue slide; s |= b; } printf("%d\n", i); break; } }