include<bits/stdc++.h>

using namespace std; double a[200005],s[200005],pos[200005]; int main(){ int n,m,l,r; scanf("%d %d",&n,&m); s[0]=1; for(int i=1;i<=n;i++){

scanf("%lf",&a[i]);
if(a[i]==0){
	s[i]=1;
	pos[i]=i;
}else{
s[i]=s[i-1]*a[i];
pos[i]=pos[i-1];	
}	

} while(m--){

scanf("%d %d",&l,&r);
double sum=0;
if(pos[r]>=l){
	printf("0.00\n");
	continue;
}else{
sum=s[r]/s[l-1];	
}
printf("%.2lf\n",sum);

} return 0; }