#include <iostream>#include <sstream>#include <cstdio>#include <climits>#include <ctime>#include <cstring>#include <cstdlib>#include <string>#include <stack>#include <map>#include <cmath>#include <vector>#include <queue>#include <algorithm>#define esp 1e-6#define pi acos(-1.0)#define inf 0x0f0f0f0f#define pb push_back#define lson l, m, rt<<1#define rson m+1, r, rt<<1|1#define mp(a, b) make_pair((a), (b))#define in freopen("solve_in.txt", "r", stdin);#define out freopen("solve_out.txt", "w", stdout);#define bug puts("********))))))");#define inout in out#define stop system("pause");#define PRD(a) printf("%dn",(a))#define PRU(a) printf("%un", (a))#define PRID(a) printf("%I64dn", (a))#define PRIU(a) printf("%I64un", (a))#define PRLU(a) printf("%llun", (a))#define PRLD(a) printf("%lldn", (a))#define SET(a, v) memset(a, (v), sizeof(a))#define READ(a, n) {REP(i, n) cin>>(a)[i];}#define REP(i, n) for(int i = 0; i < (n); i++)#define Rep(i, base, n) for(int i = base; i < n; i++)#define REPS(s, i) for(int i = 0; s[i]; i++)#define pf(x) ((x)*(x))#define Log(a, b) (log((double)b)/log((double)a))#define Srand() srand((int)time(0))#define random(number) (rand()%number)#define random_range(a, b) (int)(((double)rand()/RAND_MAX)*(b-a) + a)using namespace std;typedef long long LL;typedef unsigned long long ULL;typedef vector<int> VI;typedef pair<int,int> pii;typedef vector<pii> VII;typedef vector<pii, int> VIII;typedef VI:: iterator IT;typedef map<string, int> Mps;typedef map<int, int> Mpi;typedef map<int, pii> Mpii;typedef map<pii, int> Mpiii;int main(){ int m, p, a, b; while(scanf("%d%d%d%d", &m, &p, &a, &b) == 4){ double ans = 0; double down = -1.0/sqrt((double)a), up = sqrt((double)a); double sum = b*up; for(int i = 1; i < m; i++) if(sum - up < down) ans += pow(down, p), sum -= down; else ans += pow(up, p), sum -= up; ans += pow(sum, p); printf("%.0fn", ans); } return 0;}
