const length = parseInt( readline() )
const map = {}
for( let i = 0; i < length; i++ ) {
const [ key, value ] = readline().split(" ").map(Number)
if( map[key] ) {
map[key] += value
}else {
map[key] = value
}
}
Object.keys(map).forEach( key => {
print(`${key} ${map[key]}`)
})
const map = {}
for( let i = 0; i < length; i++ ) {
const [ key, value ] = readline().split(" ").map(Number)
if( map[key] ) {
map[key] += value
}else {
map[key] = value
}
}
Object.keys(map).forEach( key => {
print(`${key} ${map[key]}`)
})