#include <iostream>
using namespace std;
int a[100001];
int calc_length(int num)
{
int i=1,j,p,l=1,len=1;
while(i<num)
{
p=a[i];
for(j=i+1;j<=num;j++)
{
if(a[j]!=p+1)
{ i=j;
break;
}
else
{
l++; p=a[j];
i=j;
}
}
if(l>len)
{
len=l;
l=1;
}
}
return len;
}
int main() {
// your code goes here
int num,que;
scanf("%d %d",&num,&que);
int ans[que];
int i,x,y;
for(i=1;i<=num;i++)
{
scanf("%d ",&a[i]);
}
ans[0]=calc_length(num);
for(i=1;i<=que;i++)
{
scanf("%d %d",&x, &y);
a[x]=y;
ans[i]=calc_length(num);
}
for(i=0;i<=que;i++)
{
printf("%d\n",ans[i]);
}
return 0;
}
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