暴力即可。
uses math;
var
f:array[0..100000] of longint;
a,b:array[1..100] of longint;
n,m,i,j,t:longint;
begin
//assign(input,'humble.in');reset(input);
//assign(output,'humble.out');rewrite(output);
fillchar(f,sizeof(f),0);
readln(n,m);
for i:=1 to n do
read(a[i]);
f[0]:=1;
for i:=1 to m do
begin
t:=maxlongint;
for j:=1 to n do
begin
while a[j]*f[b[j]]<=f[i-1] do inc(b[j]);
t:=min(a[j]*f[b[j]],t);
end;
f[i]:=t;
end;
writeln(f[m]);
//close(input);
//close(output);
end.