//UVa1368 - DNA Consensus String
//题目:给m个长度为n的DNA序列，求一个DNA序列到所有序列的总Hamming距离最小，Hamming距离为不同字符的位置的个数。

//分析:每列找出最多重复次数。
defien A1 //1,only DNA
defien A2 //2,已AC
ifdef A1
include
include
int main(){

int T;

scanf("%d",&T);

while(T--){

//输入

int m, n;

scanf("%d %d",&m,&n);//m个n长度的

//存储

int s[n][4];

memset(s,0,sizeof(s));

char f[4]={'A','C','G','T'};

//找个数

for(int i = 0; i <= m; i++){//rows

int g,count = 0;

char ch;

//while((ch=getchar()) != '\n'){

while(scanf("%c",&ch) == 1){//every row

//getchar();

if(ch=='\n')break;

if(ch=='A')g=0;

if(ch=='C')g=1;

if(ch=='G')g=2;

if(ch=='T')g=3;

s[count][g] += 1;

count++;

}

}

//printf("%d %d %d %d %d\n",s[1][0],s[1][1],s[1][2],s[1][3],s[0][0]);

//输出

for(int j = 0; j < n; j++){

int max = 0, T = 4;

//int *pt;

while(T){

//pt = &s[j][T];

if(((s[j][T-1]) > (s[j][max])))max = T-1;

T--;

}

//printf("%d\n",s[j][T-1]);

printf("%c",f[max]);

}

putchar('\n');

}

return 0;

}
endif
ifdef A2
include
include
int main(void){

int t;

scanf("%d",&t);

while(t--){

int n,m;

scanf("%d %d",&n,&m);

char DNA[n][m+1];

for(int i=0;i<n;i++) scanf("%s",DNA[i]);

int list[4];

int num=0,num1;

for(int i=0;i<m;i++){

memset(list,0,sizeof(list));

for(int j=0;j<n;j++){

if(DNA[j][i]=='A') list[0]++;

else if(DNA[j][i]=='C') list[1]++;

else if(DNA[j][i]=='G') list[2]++;

else list[3]++;

}

int temp=0,ans;

for(int k=0;k<4;k++){

if(list[k]>temp) {

ans=k;

temp=list[k];

num1=n-list[k];

}

}

if(ans==0) printf("A");

else if(ans==1) printf("C");

else if(ans==2) printf("G");

else printf("T");

num+=num1;

}

printf("\n%d\n",num);

}

return 0;

}
endif