#include<bits/stdc++.h> using namespace std; #define REP(i,a,b) for(i=a;i<b;i++) #define rep(i,n) REP(i,0,n) #define mygc(c) (c)=getchar_unlocked() #define mypc(c) putchar_unlocked(c) void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);} void reader(int *x, int *y, int *z){reader(x);reader(y);reader(z);} int H, A, D; double res[100000]; int main(){ int i, j, k; reader(&H,&A,&D); res[0] = 0; REP(i,1,H+1){ res[i] = min(1.0 + (i-A>=0?res[i-A]:0), 1.5 + (i-D>=0?res[i-D]:0)); } printf("%.1f\n",res[H]); return 0; }