cutting

# include <bits/stdc++.h>
using namespace std;
map <long long,long long> mp;
long long S;
long long m,n;

long long calcArea(pair <long long,long long> A,pair <long long,long long> B)
{

    long long x=(B.first+B.second+A.first-A.second);
    long long y= x+2*A.second-2*A.first;
    long long S=0;
    if(y<=2*m)
    {
    	S+=(y+2*A.second)*(x-2*A.first);
       S+=(2*B.second+y)*(2*B.first-x);
    }
    else
    {
        long long x1=m+A.first-A.second;
        long long x2=B.second+B.first-m;
        S+=(m+A.second)*(x1-A.first);
        S+=2*(x2-x1)*m;
        S+=(m+B.second)*(B.first-x2);
        S=S*4;
    }
    return S;
}

bool isPointUp(pair <long long,long long> P,pair <long long,long long> A,pair <long long,long long> B)
{
    pair <long long,long long> v1;
    v1.first=B.first-A.first;
    v1.second=B.second-A.second;
    pair <long long,long long> v2;
    v2.first=P.first-A.first;
    v2.second=P.second-A.second;
    long long cross=v1.first*v2.second-v1.second*v2.first;
    return cross>=0;
}

void update(long long x,long long y)
{
    auto itr=mp.lower_bound(x);
    if(itr->first>=x&&x!=0)
        --itr;
    auto nextt=itr;
    ++nextt;
    S-=calcArea(*itr,*nextt);
    auto curr=itr;
    if(itr->first>0)
    {
        --curr;
        while(1)
        {
            if(isPointUp(*itr,{x-1,y+1},{x,y}))
                {
                    S -= calcArea(*curr,*itr);
                    mp.erase(itr);
                    itr = curr;
                    if(itr->first==0)
                        break;
                    --curr;
                }
                else
                    break;
    	}
    }
    if(itr->first==0)
        itr->second=min(itr->second,x+y);
    auto f=itr;
    itr=nextt;
    if(itr->first!=n)
    {
        ++nextt;
        while(1)
        {
            if(isPointUp(*itr,{x,y},{x+1,y+1}))
            {
                S-=calcArea(*itr,*nextt);
                mp.erase(itr);
                itr=nextt;
                if(itr->first==n)
                    break;
                ++nextt;
             }
             else
                break;
        }
    }
    if(itr->first==n)
    {
        itr->second=min(itr->second,n+y-x);
    }
    auto l=itr;
    mp[x]=y;
    itr=mp.find(x);
    S+=calcArea(*f,*itr);
    S+=calcArea(*itr,*l);
}

void init(long long N,long long M)
{
    n=N;
    m=M;
    mp[0]=m;
    mp[n]=m;
    S=calcArea({0,m},{n,m});
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    long long N,M;
    cin>>N>>M;
    init(N,M);
    long long Q;
    cin>>Q;
    long long x,y;
    while(Q--)
    {
        cin>>x>>y;
        update(x,y);
        double p=(double)S/8;
        printf("%.2f\n",p);
    }
    return 0;
}