var
m,n,k,x:qword;
i:longint;
ans:qword;
a:array[0..10000000] of longint;
function cf(i:longint):longint;
var
t,j:longint;
begin
t:=1;
for j:=1 to i do begin
t:=t*10;
end;
cf:=t;
end;
begin
readln(n,m,k,x);
for i:=0 to n-1 do begin
a[i]:=i;
end;
ans:=(cf(k)*m) mod n;
a[x]:=(a[x]+ans) mod n;
writeln(a[x]);
end.

哪里错了，为什么只有30分