#include<iostream>
#include <algorithm>
using namespace std;
int main(){
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
long n,k,x,i,negative; long long result;
while(cin>>n>>k){
long ar[100000];
negative=0;
for (i = 0; i <n; i++)
{
cin>>x;
ar[i]=x; if(x<0) negative++;
}
while(k>0){
long* pos=min_element(ar,ar+negative);
if(pos!=(ar+n)){
long postion=distance(ar,pos);
if(ar[postion]<0)ar[postion]*=-1;else break;
} else break;
k--;
}
if(k>0 && k%2!=0) ar[0]*=-1;
result=0;
for (i = 0; i <n; i++) result+=ar[i];
cout<<result<<endl;
}
return 0;
}
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3 2
1 1 -1
3 2
1 1 1
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3 1
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69 28
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