#include <bits/stdc++.h> #include <atcoder/all> using namespace std; using namespace atcoder; typedef long long int ll; typedef long double ld; #define FOR(i,l,r) for(ll i=l;i<r;i++) #define REP(i,n) FOR(i,0,n) #define RFOR(i,l,r) for(ll i=r-1;i>=l;i--) #define RREP(i,n) RFOR(i,0,n) #define ALL(x) x.begin(),x.end() #define P pair<ll,ll> #define F first #define S second #define BS(A,x) binary_search(ALL(A),x) #define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin()) #define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin()) #define COU(A,x) (UB(A,x)-LB(A,x)) template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>; //using mint=modint1000000007; using mint=modint998244353; void chmax(ll&a,ll b){a=max(a,b);} void chmin(ll&a,ll b){a=min(a,b);} signed main(){ ll a,b,N,mod=998244353;cin>>a>>b>>N; if(a==b||a==0){cout<<0<<endl;return 0;} ll g=__gcd(a*a+b*b,2*a*b),s=(a*a+b*b)/g,t=2*a*b/g; //cout<<s<<" "<<t<<endl; mint ans=max(N-s*b,0LL)%mod*(max(N-t*b,0LL)%mod)*8; if(b*b-a*a==2*a*b)ans/=2; cout<<ans.val()<<endl; return 0; }