#define _CRT_SECURE_NO_WARNINGS #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define eps 0.00000001 #define LONG_INF 10000000000000000 #define GOLD 1.61803398874989484820458 #define MAX_MOD 1000000007 #define REP(i,n) for(long long i = 0;i < n;++i) int main() { long long n, v, c; cin >> n >> c >> v; long long now = 1; long long board = 1; long long ans = c; while (now < n) { now += board; ans += v; if (now >= n) break; long long remain = n - now; long long cost = (remain + board - 1) / board; cost *= v; cost -= c; long long pre_board = now; cost -= ((remain + pre_board - 1) / pre_board)*v; if (cost >= 0) { ans += c; board = now; } } cout << ans << endl; return 0; }