#include <stdio.h>int main(){ int h,g1,d1,g2,d2,p=0; if(scanf("%d%d%d%d%d",&h,&g1,&d1,&g2,&d2)!=5) return 0; while(h>0)p+=h, h-=(p%g1==0)*d1 + (p%g2==0)*d2; printf("%d",p); return 0;}